diff --git a/crates/kind-derive/src/subst.rs b/crates/kind-derive/src/subst.rs
index 35aab281..d2b792e0 100644
--- a/crates/kind-derive/src/subst.rs
+++ b/crates/kind-derive/src/subst.rs
@@ -182,7 +182,7 @@ impl<'a> Visitor for Subst<'a> {
                 self.visit_expr(val);
                 self.visit_expr(typ);
             }
-            ExprKind::Lit { lit } => self.visit_literal(lit),
+            ExprKind::Lit { lit } => self.visit_literal(expr.range, lit),
             ExprKind::Binary { op: _, fst, snd } => {
                 self.visit_expr(fst);
                 self.visit_expr(snd);
diff --git a/crates/kind-pass/src/unbound/mod.rs b/crates/kind-pass/src/unbound/mod.rs
index db88bcd7..55d3346c 100644
--- a/crates/kind-pass/src/unbound/mod.rs
+++ b/crates/kind-pass/src/unbound/mod.rs
@@ -334,7 +334,11 @@ impl Visitor for UnboundCollector {
     fn visit_pat(&mut self, pat: &mut Pat) {
         match &mut pat.data {
             PatKind::Var(ident) => self.visit_pat_ident(ident),
-            PatKind::Str(_) => (),
+            PatKind::Str(_) => {
+                let string = &mut QualifiedIdent::new_static("String", None, pat.range);
+                self.visit_qualified_ident(&mut string.add_segment("cons").to_generated());
+                self.visit_qualified_ident(&mut string.add_segment("nil").to_generated());
+            }
             PatKind::U60(_) => (),
             PatKind::U120(_) => (),
             PatKind::F60(_) => (),
@@ -393,6 +397,19 @@ impl Visitor for UnboundCollector {
         }
     }
 
+    fn visit_literal(&mut self, range: Range, lit: &mut kind_tree::concrete::Literal) {
+        use kind_tree::concrete::Literal::*;
+
+        match lit {
+            String(_) => {
+                let string = &mut QualifiedIdent::new_static("String", None, range);
+                self.visit_qualified_ident(&mut string.add_segment("cons").to_generated());
+                self.visit_qualified_ident(&mut string.add_segment("nil").to_generated());
+            }
+            _ => (),
+        }
+    }
+
     fn visit_expr(&mut self, expr: &mut Expr) {
         match &mut expr.data {
             ExprKind::Var { name } => self.visit_ident(name),
@@ -439,7 +456,7 @@ impl Visitor for UnboundCollector {
                 self.visit_expr(val);
                 self.visit_expr(typ);
             }
-            ExprKind::Lit { lit } => self.visit_literal(lit),
+            ExprKind::Lit { lit } => self.visit_literal(expr.range, lit),
             ExprKind::Binary { op: _, fst, snd } => {
                 self.visit_expr(fst);
                 self.visit_expr(snd);
diff --git a/crates/kind-tree/src/concrete/visitor.rs b/crates/kind-tree/src/concrete/visitor.rs
index 0a789364..68ed149e 100644
--- a/crates/kind-tree/src/concrete/visitor.rs
+++ b/crates/kind-tree/src/concrete/visitor.rs
@@ -56,8 +56,8 @@ pub trait Visitor: Sized {
         walk_syntax_ctx(self, synt);
     }
 
-    fn visit_literal(&mut self, lit: &mut Literal) {
-        walk_literal(self, lit);
+    fn visit_literal(&mut self, range: Range, lit: &mut Literal) {
+        walk_literal(self, range, lit);
     }
 
     fn visit_pat_ident(&mut self, ident: &mut PatIdent) {
@@ -145,7 +145,7 @@ pub fn walk_range<T: Visitor>(_: &mut T, _: &mut Range) {}
 
 pub fn walk_syntax_ctx<T: Visitor>(_: &mut T, _: &mut SyntaxCtxIndex) {}
 
-pub fn walk_literal<T: Visitor>(_: &mut T, _: &mut Literal) {}
+pub fn walk_literal<T: Visitor>( _: &mut T, _: Range, _: &mut Literal) {}
 
 pub fn walk_constructor<T: Visitor>(ctx: &mut T, cons: &mut Constructor) {
     ctx.visit_ident(&mut cons.name);
@@ -463,7 +463,7 @@ pub fn walk_expr<T: Visitor>(ctx: &mut T, expr: &mut Expr) {
             ctx.visit_expr(typ);
         }
         ExprKind::Lit { lit } => {
-            ctx.visit_literal(lit);
+            ctx.visit_literal(expr.range, lit);
         }
         ExprKind::Binary { op: _, fst, snd } => {
             ctx.visit_expr(fst);